The present invention is directed to tube cleaning machines for cleaning the tubes and pipes of power plant equipment such as boilers, condensers, heat exchangers and so forth. In tube cleaning such equipment, an operator uses commercially available equipment such as described in U.S. Pat. Nos. 5,235,718 and 5,426,807. Such equipment comprises a rotating brush and water flush that an operator inserts into each tube to be cleaned. The equipment rotates the brush by means of a drive shaft and propels the brush and sheath encased drive shaft the full length of each tube for cleaning, provides the water flush, and withdraws the brush after the tube is so cleaned.
Tube cleaning brushes have a twisted wire spine securing bristles in a spiral or helix pattern such that a rotating brush has a natural feed rate into and through a tube by rotation in one direction, and back out of the tube by rotation in the opposite direction.
Power plant equipment may be fitted with tubes having a smooth bore or with tubes having a rifled bore to enhance heat transfer which are referred to herein as enhanced tubes. In the case of enhanced tubes, the rifling helix defines the natural feed rate of a rotating brush through the tube. With enhanced tubes, it is important to minimize slip between a rotating cleaning brush and the grooves in the tube. Excessive slip will not allow the brush bristles into the grooves thus leaving them fouled. Excessive slip occurs when rotational speed of the brush exceeds the natural feed rate of the rifling helix in the tube.
A related condition can also occur which is the pushing the brush linearly through an enhanced tube over the grooves where the brush is not rotating quickly enough.
The present invention provides a tube cleaning machine enabling an operator regulate brush speed for proper cleaning of both smooth bore and enhanced tube equipment.